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Hydrogen Diffusion Mechanism in Amorphous Silicon From D Tracer Diffusion: Theory and Experiment

Published online by Cambridge University Press:  01 January 1993

Howard M. Branz
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
Sally Asher
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
Brent P. Nelson
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
Mathieu Kemp
Affiliation:
University of North Carolina, Chapel Hill, NC 27599
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Abstract

We compare experimental diffusion studies to the results of a theoretical study of diffusion controlled by a single deep trap level. Analytic solutions for the D profiles after annealing depend on the characteristic H release time, τ, from the deep trap. At times much shorter than τ, the D profile develops exponential wings whose decay length is the mean D displacement between trapping events. The long-time D profile is a solution to the ideal diffusion equation, but with an effective diffusion coefficient that can be calculated from features of the early-time profiles. New experimental data establish the validity of the model at a range of anneal times and temperatures. We also find that the mean displacement of free H before retrapping decreases with both increased illumination and increasing anneal temperature.

Type
Research Article
Copyright
Copyright © Materials Research Society 1993

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References

REFERENCES

1.See, for example, Amorphous Silicon Materials and Solar Cells, AIP Conf. Proc. 234. edited by Stafford, B. L. (AIP, New York, 1991).Google Scholar
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